To show MysticalRommel that he really should consider using Inf, I’m taking on cystic crypt idea. I’ve compiled the combat stats, round per round, for two armies worth of 100 IPC each.
Here it is…
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Army1: 20 Arm = 100 IPC
Army2: 20 Inf + 8 Arm = 100 IPC
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Army1 attack Army2
R1
Army1: {20 * 3/6 = 10}
Army2: {[20 + 8] * 2/6 = 9.33}
R2
Army1: {11 * 3/6 = 5.5}
Army2: {[10 + 8] * 2/6 = 6}
R3
Army1: {5 * 3/6 = 2.5}
Army2: {[5 + 8] * 2/6 = 4.33}
R4
Army1: {1 * 3/6 = 0.5}
Army2: {[2 + 8] * 2/6 = 3.33}
Army2 wins with 2 Inf and 8 Arm left
Army2 attack Army1
R1
Army1: {20 * 1/6 = 3.33} + {8 * 3/6 = 4}
Army2: {20 * 2/6 = 6.67}
R2
Army1: {14 * 1/6 = 2.33} + {8 * 3/6 = 4}
Army2: {13 * 2/6 = 4.33}
R3
Army1: {9 * 1/6 = 1.5} + {8 * 3/6 = 4}
Army2: {7 * 2/6 = 2.33}
R4
Army1: {7 * 1/6 = 1.17} + {8 * 3/6 = 4}
Army2: {1 * 2/6 = 0.33}
Army2 wins with 7 Inf and 8 Arm left
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As you can see, even the impressive stack of 20 Arm is doing worse on attack than the Inf/Arm combo.